1954 antenna cable installation -- trunk end connector issue and lessons learned

[Peter R.]

I'm installing a new radio antenna cable in my '54 (the old one was mostly missing). The connector at the trunk end of the cable uses the bare center conductor of the coax as the prong that inserts into the antenna fixture on the trunk lid. What has me wondering is the fact that the coax center conductor is quite a bit smaller diameter than the receiving hole in the antenna fixture (see picture). It just doesn't look like a reliable electrical connection. Did the original antenna cable use only the bare center conductor of the coax as the prong or did the end connector have built-in thicker prong into which the center conductor was soldered? This could make for a snugger fit into the antenna fixture.

The other problem I think I'm seeing is the threading of the cable end connector versus the threading of the antenna fixture. The antenna fixture is threaded 3/8-32 (male). The end connector on the antenna cable seems to be 3/8-24 (female), but it is difficult to check its threads with total certainty because the thread gauge is awkward to use with the threads inside to the connector. But even just a visual comparison of the antenna cable end connector with a TV cable connector (which is 3/8-32) sure makes it look like the threads in my radio antenna cable are coarser, like 3/8-24. Has anyone else seen this apparent threading mismatch?

By the way, I bought the antenna cable completely assembled, as you might expect. After a few hours of failed attempts to install it, I finally decided that because of the restriction caused by the rear grommet (in a pretty inaccessible spot about a foot directly above the ground strap access hole in the right rear inner rocker panel) and the increased diameter of the cable where the ground strap attaches to it, the only way to install the cable was to remove the trunk end connector and put the cable through the rear grommet from below. I used a video inspection camera to put a fishing tape through the grommet and through the hole in the upper right corner of the trunk and then pulled a nylon rope back through the same path. Then I used the rope to pull the cable through from below, again working through the ground strap hole. Working through the same hole, I also fished a nylon rope forward to the right kick panel area and then used the roper to pull the cable into the car's interior. All in all, the job wasn't too bad, but would have been next to impossible without the camera and fishing tape. NOTE: Makers of reproduction antenna cables for the '53-54 might want to consider leaving off the rear connector, to be installed by the user after the cable is in place.

Pete

[John S.]

Re: 1954 antenna cable installation -- trunk end connector issue and lessons learned

i purchased the complete cable from grossmueller's and had all the same problems. since i was having the radio restored i sent the antenna wire and trunk fitting to jerry rudbeck. he added a sleeve to the thin center conductor for a good fit and then adjusted the radio so it worked properly with the antenna assembly. the 53 and 54 have it made with the size of hole they have for the ground strap. in 55 the hole and small plate are eliminated and the strap is pulled through a 1/8"x3/4" slit. the 53-55 judging manual has probably had many owner incorrectly modify the ground strap slot on a 55 because of it's illustration of the hole and cover.

[Dan D.]

Re: 1954 antenna cable installation -- trunk end connector issue and lessons learned

Pete, I have my original 1954 antenna cable connector and the mating flange fitting in my workshop so I went down and looked at it. I do not have a thread gauge, but it is at least 32 threads. Definitely not 24. The cable center conductor measures .013 and it has a sleeve soldered to it which makes a nice snug fit into the flange connector. The sleeve measures .095. In your photo it looks like they have added a sleeve, but it may not be the correct diameter. Mine is original, so I know .095 is correct.

I don't know what the repro guys are offering, but it should have a sleeve and it should have a fine thread in order to work. You can always add the sleeve, but the thread mismatch will mangle the plastic threads in the flange. Seeing how the plastic is soft, you could probably force the threads to mate it up, but the flange will be damaged forever.

Hope this helps.
-Dan-

[Chris S.]

Re: 1954 antenna cable installation -- trunk end connector issue and lessons learned

I also have my orig antenna cable and rear connector
both are fine thread
I too bought a repro - it fit perfect - screwed on easy and radio reception is excellent
I fished mine from the rear - after running wire and pulled it thru - pretty easy.....
I had more trouble on the drivers side with the wiring
I removed some of the bonding material to get the harness thru and did the same thing on the other side to get the cable thru
Real pain - as the harness and cable were installed prior to the upper surrounds being bonding on.....

[Peter R.]

Re: 1954 antenna cable installation -- trunk end connector issue and lessons learned

Both answers help a lot. Thank you both. I got my cable from the same source as John. The center conductor on my cable is definitely not sleeved. I know this because I had to remove the end connector in order to install the cable and then put it back on. Following Dan's example, I just went to the garage and measured my items. The bare center connector measures 0.042 inches in diameter. I measured the hole in the antenna fixture with drill bits: 5/64" (0.078) fit with a little slop; 3/32" (0.094) would not fit, althought maybe I could have forced a very tight fit. That is close to matching Dan's measurement of 0.095 for his sleeve. Both John and Dan saying that their center conductors were sleeved tells me that's the solution to that problem. I'll contact Jerry Rudbeck if I can find contact info and see if I can get a sleeve from him. John didn't mention the possible thread mismatch between the cable end connector and the antenna fixture and what, if anything, was done about it. I think my cable end connector is going to have to come off again. Then I'll check the threads more carefully without the center conductor in the way and maybe I'll have to replace it with one that is 3/8"-32.

Thanks again,

Pete

[John S.]

Re: 1954 antenna cable installation -- trunk end connector issue and lessons learned

Both answers help a lot. Thank you both. I got my cable from the same source as John. The center conductor on my cable is definitely not sleeved. I know this because I had to remove the end connector in order to install the cable and then put it back on. Following Dan's example, I just went to the garage and measured my items. The bare center connector measures 0.042 inches in diameter. I measured the hole in the antenna fixture with drill bits: 5/64" (0.078) fit with a little slop; 3/32" (0.094) would not fit, althought maybe I could have forced a very tight fit. That is close to matching Dan's measurement of 0.095 for his sleeve. Both John and Dan saying that their center conductors were sleeved tells me that's the solution to that problem. I'll contact Jerry Rudbeck if I can find contact info and see if I can get a sleeve from him. John didn't mention the possible thread mismatch between the cable end connector and the antenna fixture and what, if anything, was done about it. I think my cable end connector is going to have to come off again. Then I'll check the threads more carefully without the center conductor in the way and maybe I'll have to replace it with one that is 3/8"-32.

Thanks again,

Pete

before installing antenna wire i noticed the smaller center conductor and the problem with the threads. all parts were sent to jerry, of which i included the trunk connector. he mentioned that having the antenna wire would probably help in fine tuning proper radio reception. jerry made the necessary adjustments and all i had to do was install the parts.

[Peter R.]

Re: 1954 antenna cable installation -- trunk end connector issue and lessons learned

Thanks John. I emailed Jerry this AM and he was kind enough to reply with a bunch of pictures of the work he did on your connector. He used a center connector sleeve scavanged from a TNC 50-7-5c/133 connector (which should be readily available). I'll give that approach a try.

Pete

[John S.]

Re: 1954 antenna cable installation -- trunk end connector issue and lessons learned

pete, let me know who has that connector. i like to buy a couple.

[Troy P.]

Re: 1954 antenna cable installation -- trunk end connector issue and lessons learned

Chris, did you get your cable from Grossmuellers as well or some other source?

[Chris S.]

Re: 1954 antenna cable installation -- trunk end connector issue and lessons learned

Troy - I do believe it came from Grossmueller's - I would have to check

[Troy P.]

Re: 1954 antenna cable installation -- trunk end connector issue and lessons learned

That's the only place I've heard that sells them. Just wondering if you found another source. I'm curious because the one you got apparently did not have the originality defects reported by the others.

[Joseph T.]

Re: 1954 antenna cable installation -- trunk end connector issue and lessons learned

Pete

Here is a photo of the original antenna trunk connection in my 15,000 mile car...purchased from original owner.

Joe

54 antenna.jpg

[Peter R.]

Re: 1954 antenna cable installation -- trunk end connector issue and lessons learned

To close out this thread and increase its value to future users, I wanted to post what I finally did to resolve the problem with the trunk-end connector on my reproduction antenna cable. I had earlier removed the trunk-end connector from the cable in order to install the cable up through the rear grommet and into the trunk. While the connector was off the cable, I mounted it in a vice with rubber jaw pads, and ran a 3/8-32 bottoming tap into the connector ferrule. While the original threads in the ferrule were 3/8-24, the tap was able to replace them with functional (although not pretty) 3/8-32 threads that would be compatible with the threads on the trunk lid antenna fixture. Then I put a one-inch long piece of 3/8" heat-shrink tubing over the trunk end of the cable, put the connector back on the cable, crimped its retaining band to hold it in place, and applied heat to the heat-shrink tubing after locating it just aft of the connector in order to cover the retaining ring. Then I cut a short section (about 1/2" long--same length as the cable center conductor sticking out of the connector) of 3/32" O.D. brass tubing. The small piece of tubing was to be used over the center conductor of the cable to create a nice snug, electrically reliable connection when the cable was connected to the trunk antenna fixture. Before putting the sleeve on the center conductor, I chamfered the end of the sleeve that would be inserted into the trunk antenna fixture in order to ease the insertion process. Then I slipped the sleeve over the center conductor of the cable until it bottomed in the connector and soldered it in place. The trunk end of the cable was done at this point. The threads on my trunk antenna fixture were a little messy so I very carefully ran a 3/8-32 die over its threads. Then I joined the cable with its connector to the trunk fixture by inserting the sleeved center conductor into the center hole of the fixture and threading the ferrule onto the fixture--I did this in small steps so as not to overstress and strip the plastic threads on the antenna fixture--push the connector onto the fixture, twist the ferrule, push the connector on further, twist the ferrule more, push the connector more, twist the ferrule more, continuing until the connector was fully engaged on the fixture. The end result was a nice snug, reliable fit of the cable connector and its center conductor into the antenna fixture with the ferrule fully engaged.

[Rob M.]

Re: 1954 antenna cable installation -- trunk end connector issue and lessons learned

Thanks for taking the time to document this resolution Peter, I'll probably need this posting in a year or two when I will be working on my own 1954 restoration! You might want to post it to Vinnie as well to get it in the Restorer!!!